1. Field of the Invention
The present invention relates to a nonwoven fabric for printing, which has good tearing strength and can provide printing finish as good as an art paper at a low cost.
2. Prior Art
Conventionally, various types of nonwoven fabrics have been known as material which could be used in many industrial fields including the civil engineering, carpet and furniture industry, and durable paper products, throwaway materials and coating fabrics. Such nonwoven fabrics are generally classified into a filament nonwoven fabric and a staple nonwoven fabric from the viewpoint of length of fibres which composes the nonwoven fabrics. The filament nonwoven fabric is composed of substantially endless filament fibres which are discharged through a spinning nozzle, whereas the staple nonwoven fabric generally comprises staple fibres of 5-100 mm in length. In respect of the tearing strength, it is preferred to use the filament nonwoven fabric, particularly a high-density filament nonwoven fabric made from synthetic resin such as polyethylene and polypropylene.
On the other hand, to guarantee excellent appearance for products made with such a nonwoven fabric, it is desired to give a high-quality printing process to the nonwoven fabric. Conventionally, for printing onto the filament nonwoven fabric made from polyethylene or polypropylene, there should be required use of expensive special ink such as synthetic-paper ink, ultraviolet-curing ink and electron-beam-curing ink.
However, use of the synthetic-paper ink will greatly impair the printing workability. While, when the UV-curing ink or electron-beam-curing ink is used, an expensive UV-ray generator or electron-beam generator must be employed for curing such ink, so that it becomes difficult to carry out the printing at a low cost. Moreover, in case of UV-curing ink, even after the ink is dried, residual reaction initiator and unreacted monomer smell unpleasantly, thereby deteriorating the working atmosphere.
The offset printing is widely known as a suitable method for attaining a low-cost and high-quality printing. However, such synthetic resin as polyethylene and polypropylene will be affected by a high-boiling-point solvent contained in the offset print ink, so that when the offset printing is carried out onto the nonwoven fabric made from polyethylene or polypropylene, the nonwoven fabric is swelled and unevenness occurs on the surface thereof. Moreover since the nonwoven fabric is originally inferior in the surface smoothness resulting in a poor ink-transfer property, that is, an ink attached to a blanket of an offset printing machine would not readily be transferred to the surface of the nonwoven fabric, the printing quality can not be improved as high as the level of the art papers. The ink-setting property of the nonwoven fabric is also poor so that when a plurality of the printed nonwoven fabric are stacked one another, the ink once transferred to the surface of the underlying nonwoven fabric could be re-transferred to the underside of the overlying one, this being known in general as a matter of set-off.